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What are comments?

Comments are non-executable annotations in a program that are used to explain or document the code. They are ignored by the compiler and do not affect the program's execution. Comments are essential for improving the readability and maintainability of code, especially for complex programs.

Types of comments in Kotlin

Kotlin supports two types of comments:

Single-line comments: Single-line comments start with two forward slashes (//) and end with the end of the line. Any text between the slashes is treated as a comment. For example:

 

// This is a single-line comment

 

Multi-line comments: Multi-line comments, also known as block comments, start with /* and end with */. Any text between the slashes is treated as a comment. Multi-line comments can span multiple lines and are useful for explaining complex code blocks or providing more detailed documentation. For example:

 

/*

This is a multi-line comment

that spans multiple lines.

*/

 

Uses of comments in Kotlin

Comments have several important uses in Kotlin programming:

Explaining code: Comments can be used to explain the purpose of code blocks, variable declarations, function parameters, and other programming constructs. This makes the code more self-explanatory and easier to understand for other developers.

Documenting code: Comments can be used to document the overall structure, design, and decisions made in the code. This documentation is valuable for future reference and maintenance of the program.

Disabling code: Comments can be used to temporarily disable code blocks without deleting them. This is useful for testing different code paths or experimenting with alternative approaches.

Adding notes and reminders: Comments can be used to add notes, reminders, or to-do items for future reference. This helps keep track of pending tasks and improvements that can be addressed later.

Examples of using comments in Kotlin

Here are some examples of how comments are used in Kotlin code:

Explaining a variable declaration:

 

// This variable stores the current user's name

var userName: String = "JohnDoe"

 

Documenting a function's purpose:

 

/**

 * Calculates the sum of two numbers.

 *

 * @param num1 The first number to be added

 * @param num2 The second number to be added

 * @return The sum of the two numbers

 */

fun sum(num1: Int, num2: Int): Int {

  return num1 + num2

}

 

Disabling code for testing:

 

// This code is temporarily disabled for testing purposes

// val invalidInput = readLine()!!.toInt()

 

Adding notes and reminders:

 

// TODO: Implement error handling for invalid user input

// Remember to update the database with the new user information

 

Best practices for writing comments

Here are some best practices for writing effective comments in Kotlin:

Use clear and concise language: Comments should be written in plain English that is easy to understand for other developers. Avoid using jargon or overly technical terms.

Be specific and relevant: Comments should be specific to the code they are explaining or documenting. Avoid general or irrelevant comments that don't provide any additional information.

Use consistent formatting: Use consistent indentation and spacing to make comments visually appealing and easy to read.

Use comments judiciously: Don't overcomment your code. Comments should be used to explain non-obvious or complex parts of the code, not to repeat the code itself.

Use comments to document decisions: Explain the reasons behind non-obvious design choices or implementation decisions. This helps other developers understand the rationale behind the code.

Use comments to update code changes: When making significant changes to the code, add comments to explain the changes and the reasons behind them. This helps keep the code history understandable.

By following these best practices, you can ensure that your comments are helpful, informative, and make your code more readable and maintainable.